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Information on gene action controlling the inheritance of quantitative traits is essential for selecting parents for hybridization and multiline varieties. Twenty hybrids obtained through 5 × 5 diallel mating with their parents were established on Teaching and Research Farm, Federal University of Agriculture, Abeokuta, Nigeria, in September 2018 using Randomized Complete Block Design in three replicates. The plants were observed for numbers of days to 50% flowering, plant height at flowering, stem girth, number of branches per plant, plant height at maturity, number of fruits per plant, fruit weight, fruit length, fruit width, and fruit yield per plant. Data were subjected to variance analysis, General and Specific Combining abilities were estimated, and gene effects and parameter ratios were done using Hayman’s method. Mid- and better-parent heterosis were estimated using Allard’s procedure. Genotype ‘NGB00356’ was the most desirable parent for earliness and the number of fruits per plant, while hybrid ‘NGB00347’ × ‘NGB00356’ was the best hybrid for fruit yield per plant. ‘NGB00356’, with its significant and positive general combining ability value for the number of fruits per plant, can be used as a parent in a hybridization program for yield improvement in okra. [ABSTRACT FROM AUTHOR]

Regulatory mutations affecting the expression level and pattern of dosage-sensitive genes can create dosage imbalance in cells affected by the expression change. The deleterious effect of dosage imbalance is higher in homozygous and lower in heterozygous individuals. Pleiotropism of regulatory mutations is possible. In addition to the dosage-sensitive trait, the mutation may engender a dominant advantageous trait. Individuals that are heterozygous for such mutations will be fitter than the homozygotes. Pleiotropism may help explain heterosis, the vigor displayed by hybrids. Hybrids are heterozygous at many loci, causing transgressive fitness compared with homozygous parents. Adaptive evolution often involves structural variation affecting genes or cis -regulatory changes that engender novel and favorable gain-of-function gene regulation. Such mutation could result in a favorable dominant trait. At the same time, the gene product could be dosage sensitive if its change in concentration disrupts another trait. As a result, the mutant allele would display dosage-sensitive pleiotropy (DSP). By minimizing imbalance while conserving the favorable dominant effect, heterozygosity can increase fitness and result in heterosis. The properties of these alleles are consistent with evidence from multiple studies that indicate increased fitness of heterozygous regulatory mutations. DSP can help explain mysterious properties of heterosis as well as other effects of hybridization. [ABSTRACT FROM AUTHOR]

The study quantified breed effects and putative non-additive genetic variation for quantitative and qualitative slaughter and skin traits involving three ostrich breeds: South African Black (SAB), Zimbabwean Blue (ZB), and Kenyan Red (KR) ostriches. Such data from contemporary slaughter groups with all three pure breeds represented were analyzed together (SAB: n = 457; ZB: n = 74; KR: n = 50). Two 2 × 2 diallel crossbreeding designs were used to assess crosses of ZB and KR birds with the SAB strain. Subsequently, the data from SAB, ZB and their reciprocal crosses, slaughtered together; as well as the data from SAB and KR ostriches, along with their reciprocal crosses, respectively, were analyzed separately. ZB and KR birds outperformed SAB birds for most size-related slaughter and skin traits. Linear contrasts were used to distinguish the effects of breed, heterosis, and the dam line. For the ZB x SAB design, additive breed effects were significant for slaughter weight (10.4%), crust skin size (3.9%) and nodule shape score (1.6%) (all P < 0.05). Significant heterosis were found for slaughter weight (4.3%), crust skin size (1.7%) and nodule size score (3.7%) (P < 0.05). Dam line effects were observed for skin weight (4.1%) and hair follicle score (4.1%). In the KR x SAB design, additive breed effects were like outcomes for the ZB x SAB design. Heterosis estimates were significant (P < 0.05) for slaughter weight (5.8%), crust skin size (2.9%), crown length (1.7%) and nodule size score (4.4%). Dam line effects were significant for slaughter weight (3.7%) and nodule size score (3.8%). In conclusion, ZB and KR birds outperformed their SAB contemporaries for size and size-related traits. Crossbreeding with these genotypes could improve some size-related traits over the mid-parent value of purebreds. [ABSTRACT FROM AUTHOR]

Background: Two-line hybrid wheat technology system is one way to harness wheat heterosis both domestically and internationally. Seed vigor is a crucial parameter for assessing seed quality, as enhanced seed vigor can lead to yield increments of over 20% to a certain extent. MicroRNAs (miRNAs) were known to participate in the development and vigor of seed in plants, but its impact on seed vigor in two-line hybrid wheat remains poorly elucidated. Results: The hybrid (BS1453/11GF5135) wheat exhibited superiority in seed vigor and anti-aging capacity, compared to its male parent (11GF5135, MP) and female parent (BS1453, FP). We identified four miRNAs associated with seed vigor, all of which are novel miRNAs. The majority of targets of miRNAs were related to ubiquitin ligases, kinases, sucrose synthases and hydrolases, involving in starch and sucrose metabolism, hydrolysis, catalysis, plant hormone signal transduction, and other pathways, which played crucial roles in seed development. Additionally, we also found miR531 was differentially expressed in both male parent and hybrid, and its target gene was a component of the E1 subunit of α-ketoate dehydrogenase complex, which interacted with dihydrolipoamide acetyltransferase (E2) and dihydrolipoyl dehydrogenase (E3). Finally, We established a presumptive interaction model to speculate the relationship of miR531 and seed vigor. Conclusions: This study analyzed the seed vigor of two-line hybrid wheat, and screened seed vigor-related miRNAs. Meanwhile speculated the genetic relationship of hybrid and parents, in terms of miRNAs. Consequently, the present study provides new insights into the miRNA-mediated gene and protein interaction network that regulates seed vigor. These findings hold significance for enhancing the yield and quality of two-line hybrid wheat, facilitating its future applications. [ABSTRACT FROM AUTHOR]

Maize is one of the most successful crops in utilizing heterosis which significantly improves maize stresses resistance and yield. Drought is a destructive abiotic stress that significantly reduces crop yield, particularly in maize. Drought stress and rewatering frequently occur during the growth and development of maize; however, themolecular mechanisms of heterosis under drought stress and re-watering have rarely been systematically investigated. Zhengdan7137 and Zhengdan7153 are two maize hybrid varieties with robust heterosis, and separately belongs to the SS×NSS and Reid×Tangsipingtou heterotic groups. 54 transcriptomes of these two hybrids and their parental inbred lines were analyzed under well-watering (WW), waterdeficit (WD), and re-watering (RW) conditions using RNA-Seq. In this study, we identified 3,411 conserved drought response genes (CDRGs) and 3,133 conserved re-watering response genes (CRRGs) between Zhengdan7137 and Zhengdan7153. When comparing CDRGs and CRRGs to overdominance and underdominance genes, we identified 303 and 252 conservative drought response overdominance genes (DODGs) and underdominance genes (DUDGs), respectively, and 165 and 267 conservative re-watering response overdominance genes (RODGs) and underdominance genes (RUDGs), respectively. DODGs are involved in stress response-related processes, such as L-phenylalanine metabolism, carbohydrate metabolism, and heat response, whereas DUDGs are associated with glucose metabolism, pentose-phosphate shunt, and starch metabolism. RODGs and RUDGs contribute to the recovery of hybrids from drought stress by upregulating cell propagation and photosynthesis processes, and repressing stress response processes, respectively. It indicated overdominant and underdominant genes conservatively contributed to hybrid heterosis under drought stress. These results deepen our understanding of the molecular mechanisms of drought resistance, uncover conservative molecular mechanisms of heterosis under drought stress and re-watering, and provide potential targets for improving drought resistance in maize. [ABSTRACT FROM AUTHOR]

Nicotine exhibits obvious heterosis, which can be used to create Nicotiana tabacum L. (tobacco) varieties with varying nicotine content. However, the reasons for the formation of nicotine heterosis and its relationship to nicotine transport and accumulation remain unknown. This study conducted a comprehensive analysis of six tobacco hybrids with varying heterosis levels and their parent materials from various aspects, such as phenotype, physiology, and transcriptomics. The results showed that the direct path coefficient of transport heterosis to nicotine heterosis was highest in hybrids, at 0.98, and a highly significant positive correlation between the two. The plant height, thick stalk circumference, large flow of tissue fluid in the stalk, and high nicotine concentration of tobacco were the underlying factors that led to the strong nicotine transport capacity of hybrids. The formation of nicotine transport heterosis in hybrids was mainly influenced by non-additive gene effects (accounting for 89.93%), with over-dominant effects playing a dominant role (accounting for 58.79%). Among non-additive expression DEGs, nicotine transporter related multi antimicrobial extrusion protein, drug/metabolite transporter, ABC family transporter, and glutathione S-transferase were significantly upregulated in hybrid strains. The RT-qPCR results indicated that these genes related nicotine transport also exhibited heterosis at the expression level. Our results revealed that the formation of nicotine heterosis is mainly achieved by enhancing the nicotine transport capacity in hybrids. The results are not only beneficial for promoting the theoretical study of nicotine heterosis in tobacco and the breeding and utilization of hybrids, but are also of great significance for guiding nicotine production and promoting its multipurpose utilization. [ABSTRACT FROM AUTHOR]

Parental epigenetic asymmetries, which contribute to the monoallelic expression of genes known as imprints, play a critical role in seed development in flowering plants. Primarily, differential DNA methylation patterns and histone modifications on parental alleles form the molecular basis of gene imprinting. Plants predominantly exhibit this non-Mendelian inheritance phenomenon in the endosperm and the early embryo of developing seeds. Imprinting is crucial for regulating nutrient allocation, maintaining seed development, resolving parental conflict, and facilitating evolutionary adaptation. Disruptions in imprinted gene expression, mediated by epigenetic regulators and parental ploidy levels, can lead to endosperm-based hybridization barriers and hybrid dysfunction, ultimately reducing genetic diversity in plant populations. Conversely, imprinting helps maintain genetic stability within plant populations. Imprinted genes likely influence seed development in various ways, including ensuring proper endosperm development, influencing seed dormancy, and regulating seed size. However, the functions of most imprinted genes, the evolutionary significance of imprinting, and the long-term consequences of imprinting disruptions on plant development and adaptation need further exploration. Thus, it is clear that research on imprinting has immense potential for improving our understanding of plant development and ultimately enhancing key agronomic traits. This review decodes the possible genetic and epigenetic regulatory factors underpinning genomic imprinting and their positive and negative consequences on seed development. This study also forecasts the potential implications of exploiting gene imprinting for crop improvement programs. [ABSTRACT FROM AUTHOR]

Crossbreeding is a widely adopted practice in the livestock industry, leveraging the advantages of heterosis and breed complementarity. The prediction of Crossbred Performance (CP) often relies on Purebred Performance (PB) due to limited crossbred data availability. However, the effective selection of purebred parents for enhancing CP depends on non-additive genetic effects and environmental factors. These factors are encapsulated in the genetic correlation between crossbred and purebred populations (rpc). In this study, a two-way crossbreeding simulation was employed to investigate various strategies for integrating data from purebred and crossbred populations. The goal was to identify optimal models that maximize CP across different levels of rpc. Different scenarios involving the selection of genotyped individuals from purebred and crossbred populations were explored using ssGBLUP (single-step Genomic Best Linear Unbiased Prediction) and ssGBLUP-MF (ssGBLUP with metafounders) models. The findings revealed an increase in prediction accuracy across all scenarios as rpc values increased. Notably, in the scenario incorporating genotypes from both purebred parent breeds and their crossbreds, both ssGBLUP and ssGBLUP-MF models exhibited nearly identical predictive accuracy. This scenario achieved maximum accuracy when rpc was less than 0.5. However, at rpc = 0.8, ssGBLUP, which exclusively included sire breed genotypes in the training set, achieved the highest overall prediction accuracy at 73.2%. In comparison, the BLUP-UPG (BLUP with unknown parent group) model demonstrated lower accuracy than ssGBLUP and ssGBLUP-MF across all rpc levels. Although ssGBLUP and ssGBLUP-MF did not demonstrate a definitive trend in their respective scenarios, the prediction ability for CP increased when incorporating both crossbred and purebred population genotypes at lower levels of rpc. Furthermore, when rpc was high, utilizing paternal genotype for CP predictions emerged as the most effective strategy. Predicted dispersion remained relatively similar in all scenarios, indicating a slight underestimation of breeding values. Overall, the rpc value emerged as a critical factor in predicting CP based on purebred data. However, the optimal model to maximize CP depends on the factors influencing rpc. Consequently, ongoing research aims to develop models that optimize purebred selection, further enhancing CP. [ABSTRACT FROM AUTHOR]

Background: The additive model of inheritance assumes that heterozygotes (Aa) are exactly intermediate in respect to homozygotes (AA and aa). While this model is commonly used in single-locus genetic association studies, significant deviations from additivity are well-documented and contribute to phenotypic variance across many traits and systems. This assumption can introduce type I and type II errors by overestimating or underestimating the effects of variants that deviate from additivity. Alternative genotype encoding strategies have been explored to account for different inheritance patterns, but they often incur significant computational or methodological costs. To address these challenges, we introduce PAGER (Phenotype Adjusted Genotype Encoding and Ranking), an efficient pre-processing method that encodes each genetic variant based on normalized mean phenotypic differences between diallelic genotype classes (AA, Aa, and aa). This approach more accurately reflects each variant's true inheritance model, improving model precision while minimizing the costs associated with alternative encoding strategies. Results: Through extensive benchmarking on SNPs simulated with both binary and continuous phenotypes, we demonstrate that PAGER accurately represents various inheritance patterns (including additive, dominant, recessive, and heterosis), achieves levels of statistical power that meet or exceed other encoding strategies, and attains computation speeds up to 55 times faster than a similar method, EDGE. We also apply PAGER to publicly available real-world data and identify a novel, relevant putative QTL associated with body mass index in rats (Rattus norvegicus) that is not detected with the additive model. Conclusions: Overall, we show that PAGER is an efficient genotype encoding approach that can uncover sources of missing heritability and reveal novel insights in the study of complex traits while incurring minimal costs. [ABSTRACT FROM AUTHOR]

The hybrid grouper (Cromileptes altivelas, ♀ × Epinephelus lanceolatus, ♂) is an economically important aquaculture species that exhibits certain growth advantages compared to its female parent, Cromileptes altivelas. However, the current understanding of the molecular mechanisms underlying the growth of hybrid groupers is lacking. Herein, we performed full-length transcriptome sequencing and next-generation sequencing on the hybrid grouper and its parents to identify growth-related genes and comprehensively analyze the regulatory mechanism of growth heterosis in the hybrid grouper. Approximately 44.70, 40.44, and 45.32 Gb of single-molecule real-time sequencing data were generated in C. altivelas (Cal), E. lanceolatus (Ela), and the hybrid (Hyb), which were combined into 204,322 non-redundant isoforms using the PacBio sequencing platform. Differentially expressed genes (DEGs) were identified between Hyb and Cal (3,494, 2,125, and 1,487 in brain, liver, and muscle tissues, respectively) and Hyb and Ela (3,415, 2,351, and 1,675 in brain, liver, and muscle tissues, respectively). Then, 27 DEGs (13 in the brain and 14 in the muscle) related to growth traits were identified using cluster and correlation network analysis. Quantitative RT-PCR validated 15 DEGs consistent with transcriptome sequencing (RNA-seq) trends. The Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis revealed that these 15 genes were mainly involved in regulating the actin cytoskeleton, suggesting that this pathway plays an essential role in fish growth. In addition, we found that the phosphatase and tensin homologue (PTEN) is a key regulator of growth heterosis in Hyb. These results shed light on the regulatory mechanism of growth in the Hyb, which is important for marker-assisted selection programs to improve the growth quality of groupers. [ABSTRACT FROM AUTHOR]

High-quality red/dry chilli for spice, pharmaceutical and medicinal purposes is a major goal in chilli breeding. The male sterile lines have greater potential for the exploitation of heterosis in chilli to achieve this objective. Genetic male sterile lines with special traits like destalking and ability to withstand high rainfall were involved in heterosis breeding to identify hybrids for commercial and industrial purposes. Forty F1 hybrids were developed by crossing 4 diverse GMS lines with 10 testers using Line × Tester mating design to estimate heterosis, combing ability and gene action. The experiment involving 14 parents and 40 F1s, along with standard variety 'CH-27' was laid out in α-lattice square design in three replications during summer 2020 and 2021. The GMS lines MS 9-2 and MS 26-1 along with testers DPCh 10, VVG, DPCh 40 and Him Palam Mirch-2 showed significant GCA for marketable red/dry fruit yield and majority of their component traits. Ten F1 hybrids were identified with superiority for fruit yield based on mean performance, significant heterosis and SCA effects, providing an opportunity to utilize them in value-added products and dried spice purposes viz., MS 9-2 × HPM-2, MS 11-2 × DPCh 40, MS 9-2 × DPCh 40 and MS 9-2 × DPCh 101 with erect fruiting habit and that of MS 9-2 × DPCh 10, MS 26-1 × DPCh 10, MS 9-2 × PBC 535, MS 26-1 × VVG, MS 29-2 × DPCh 10 and MS 26-1 × DPCh 22- C with pendent fruits. The non-additive gene action was predominant in the expression of fruit yield, total red fruits/plant, oleoresin and capsanthin. A significant positive correlation among SCA, economic heterosis and per se performance is an indicative to identify superior hybrids. Multi-location testing of these hybrids shall pave way to exploit them commercially by making them available to the farmers. [ABSTRACT FROM AUTHOR]

The genetic analysis of potato is hampered by the complexity of tetrasomic inheritance. An ongoing effort aims to transform the clonally propagated tetraploid potato into a seed-propagated diploid crop, which would make genetic analyses much easier owing to disomic inheritance. Here, we construct and report the large-scale genetic and heterotic characteristics of a diploid F2 potato population derived from the cross of two highly homozygous inbred lines. We investigate 20,382 traits generated from multi-omics dataset and identify 25,770 quantitative trait loci (QTLs). Coupled with gene expression data, we construct a systems-genetics network for gene discovery in potatoes. Importantly, we explore the genetic basis of heterosis in this population, especially for yield and male fertility heterosis. We find that positive heterotic effects of yield-related QTLs and negative heterotic effects of metabolite QTLs (mQTLs) contribute to yield heterosis. Additionally, we identify a PME gene with a dominance heterotic effect that plays an important role in male fertility heterosis. This study provides genetic resources for the potato community and will facilitate the application of heterosis in diploid potato breeding. An ongoing effort aims to transform the clonally propagated tetraploid potato to a seed-propagated diploid crop, but our understanding of it disomic inheritance is limited. Here, the authors report genetic basis of heterosis in the elite hybrid potato and identify a male fertility-related PME gene with dominance heterotic effect. [ABSTRACT FROM AUTHOR]

Heterosis, recognized for improving crop performance, especially in the first filial (F1) generation, remains an area of significant study in the tobacco industry. The low utilization of leaf veins in tobacco contributes to economic inefficiency and resource waste. Despite the positive impacts of heterosis on crop genetics, investigations into leaf-vein ratio heterosis in tobacco have been lacking. Understanding the mechanisms underlying negative heterosis in leaf vein ratio at the molecular level is crucial for advancing low vein ratio leaf breeding research. This study involved 12 hybrid combinations and their parental lines to explore heterosis associated with leaf vein ratios. The hybrids displayed diverse patterns of positive or negative leaf vein ratio heterosis across different developmental stages. Notably, the F1 hybrid (G70 × Qinggeng) consistently exhibited substantial negative heterosis, reaching a maximum of -19.79% 80 days after transplanting. A comparative transcriptome analysis revealed that a significant proportion of differentially expressed genes (DEGs), approximately 39.04% and 23.73%, exhibited dominant and over-dominant expression patterns, respectively. These findings highlight the critical role of non-additive gene expression, particularly the dominance pattern, in governing leaf vein ratio heterosis. The non-additive genes, largely associated with various GO terms such as response to abiotic stimuli, galactose metabolic process, plant-type cell wall organization, auxin-activated signaling pathway, hydrolase activity, and UDP-glycosyltransferase activity, were identified. Furthermore, KEGG enrichment analysis unveiled their involvement in phenylpropanoid biosynthesis, galactose metabolism, plant hormone signal transduction, glutathione metabolism, MAPK signaling pathway, starch, and sucrose metabolism. Among the non-additive genes, we identified some genes related to leaf development, leaf size, leaf senescence, and cell wall extensibility that showed significantly lower expression in F1 than in its parents. These results indicate that the non-additive expression of genes plays a key role in the heterosis of the leaf vein ratio in tobacco. This study marks the first exploration into the molecular mechanisms governing leaf vein ratio heterosis at the transcriptome level. These findings significantly contribute to understanding leaf vein ratios in tobacco breeding strategies. [ABSTRACT FROM AUTHOR]

Modeling is essential in biosciences but the information that can be obtained is only as good as the experimental system used to retrieve it. The selection of animal models is not based on their specific relevance to human disease but rather on historical reasons related to scientific tradition and the availability of tools that can further advance mechanistic studies. Mus musculus is the model of choice in research, and especially the inbred strains. These are considered wild type, albeit their survival in the wild is doubted and inherent differences with human physiology are recognized. Failures in the translation of preclinical findings to clinical practice are widely recognized, but effort is directed towards the improvement of existing instead of the adoption of new models. Disengagement from the traditional models, especially Mus , may fuel the discovery and translation of preclinical findings to clinical practice. Historical reasons resulted in the almost exclusive use of a few species, most prominently Mus musculus , as the mainstream models in biomedical research. This selection was not based on Mus 's distinctive relevance to human disease but rather to the pre-existing availability of resources and tools for the species that were used as models, which has enabled their adoption for research in health sciences. Unless the utilization and range of nontraditional research models expand considerably, progress in biomedical research will remain restricted within the trajectory that has been set by the existing models and their ability to provide clinically relevant information. [ABSTRACT FROM AUTHOR]

• Salvia multicaulis (wild) × Salvia officinalis (cultivated) produced F1 hybrid. • F1 hybrid has the highest content of rosmarinic acid and quercetin. • PAL and CYP expressions strongly correlate with rosmarinic acid content. • Cineole contents negatively correlate with the expression of the CS gene. • Salvia has antioxidant, anticancer, anti-inflammatory, antibacterial effects. The Salvia genus, particularly the wild genotypes, received significant attention due to its antibacterial, antioxidant, antiviral, and anticancer properties. Crossbreeding wild and cultivated plants can conserve the genetic resources of wild plants and develop new hybrids with high yields and high resistance to climatic changes. In this study, Salvia multicaulis (P1, wild) and Salvia officinalis (P2, cultivated) have been crossed to produce a novel hybrid (F1 hybrid) in the Saint Catherin protectorate - Egypt. In P1, P2, and F1 hybrid, heterosis, phytochemical composition, gene expression of PAL (Phenylalanine ammonia-lyase), RAS1 (Rosmarinic acid synthase I), CYP (Cytochrome P450), and CS (1,8-Cineole synthase), besides antioxidant, anticancer, anti-inflammatory, and antibacterial effects were assessed. The F1 hybrid recorded the highest means of plant height in the two seasons. Heterosis over the mid-parents was positively associated with various traits, including stem thickness, number of branches, fresh yield, and percentage of oil in both seasons. Total phenolic and flavonoid content were found in the following order: P2 > P1 > F1. DPPH antioxidant effect was found in the following order: P2 > F1 > P1. The F1 hybrid had the highest content of rosmarinic acid (12.379 mg/g), quercetin (0.595 mg/g), and naringenin (0.152 mg/g), followed by P1 and P2. The 1,8-cineol and α-pinene were the main compounds in the essential oils of P1, P2, and F1. The 1,8-cineol was found in the following order: P2 > F1 > P1, while α-pinene was found in the following order: P1 > F1 > P2. The RAS1 expression showed a weak correlation with the concentration of rosmarinic acid, while the expressions of PAL and CYP were strongly correlated with the concentrations of main phenolics, including rosmarinic acid, quercetin, and naringenin. The 1,8-cineol content was negatively correlated with the expression of the CS gene. The P2 extract and the F1 hybrid essential oil showed potent anticancer, anti-inflammatory, and antibacterial properties. Crossbreeding S. multicaulis (P1, wild) and S. officinalis (P2, cultivated) in this study developed a new hybrid (F1) with good growth characteristics, high essential oil yields, high levels of bioactives, and good bioactivity. This makes it suitable for large-scale production for use in food and pharmaceutical applications. [ABSTRACT FROM AUTHOR]

In the context of rapidly increasing population and diversified market demands, the steady improvement of yield and quality in horticultural crops has become an urgent challenge that modern breeding efforts must tackle. Heterosis, a pivotal theoretical foundation for plant breeding, facilitates the creation of superior hybrids through crossbreeding and selection among a variety of parents. However, the vast number of potential hybrids presents a significant challenge for breeders in efficiently predicting and selecting the most promising candidates. The development and refinement of effective hybrid prediction methods have long been central to research in this field. This article systematically reviews the advancements in hybrid prediction for horticultural crops, including the roles of marker-assisted breeding and genomic prediction in phenotypic forecasting. It also underscores the limitations of some predictors, like genetic distance, which do not consistently offer reliable hybrid predictions. Looking ahead, it explores the integration of phenomics with genomic prediction technologies as a means to elevate prediction accuracy within actual breeding programs. [ABSTRACT FROM AUTHOR]

Sorghum (Sorghum bicolor) has the ability to inhibit the conversion of ammonium to nitrate (biological nitrification inhibition [BNI]) in the rhizosphere, which in turn prevents the loss of bioavailable nitrogen. Sorgoleone is a lipidic compound secreted by sorghum root hairs and is responsible for roughly 60% of BNI activity in sorghum. Previous studies revealed variation in sorgoleone secretion among different accessions and cultivars. However, little information is available regarding the genetic inheritance of sorgoleone secretion in sorghum. To increase sorgoleone through breeding, an understanding of the inheritance of this trait is required. In this study, 21 seed parents and 21 pollinator parents from the Texas AgriLife Research sorghum breeding program were crossed in an incomplete factorial design to generate 158 hybrids, and sorgoleone secretion from both hybrids and inbreds was quantified. There was significant variation in sorgoleone secretion across hybrids and inbred lines, and small but significant mid‐parent heterosis was observed in the hybrids. A linear mixed model analysis to calculate general and specific combining abilities for inbred parents and hybrids detected significant genetic effects for the male, the female, and male × female interactions (p < 0.001). Broad‐sense heritability was high (H2${{H}^2}$ = 0.87), while narrow‐sense heritability for the seed parents and pollinator parents was moderate (Hf2$H_f^2$= 0.35 and Hm2$H_m^2$ = 0.39, respectively). These results indicate that sorgoleone exudation is primarily driven by additive genetic effects, but dominance effects are important for optimum production. These findings indicate that selection for increased sorgoleone root exudation among elite, adapted grain sorghum hybrids and inbred should be effective. [ABSTRACT FROM AUTHOR]

ABSTRACT The leguminous chickpea is a good source of protein, but its yield potential is frequently constrained by biotic stresses, primarily Helicoverpa armigera, a major havoc for cultivation of the crop. To develop host plant resistance for minimizing the losses due to the pod borer, five kabuli parents with desired traits for pod borer tolerance were crossed in diallel mating design to produce 10 crosses which were analysed for traits related to pod borer and nutrition. Based on correlation studies, trichome density was found positively correlated with phenol content, but both the traits were negatively associated with number of damaged seeds. Therefore, the tolerant genotypes were identified on the basis of phenol content, trichome density, number of damaged seeds and field rating. Among parents ICC 12197 was found superior in terms of yield and borer tolerance features with an intermediate pest resistance susceptible rating in addition to higher Fe content. However, significant sca effects for higher phenol content and seed yield in ICC 11764 × ICC 14190 were recorded with reduced number of damaged seeds in addition to higher Fe and Zn content. It was observed that the specific combination involved good and poor combiners for each trait. The same cross also showed significant standard heterosis in desirable direction for phenol content, trichome density, number of damaged seeds and seed yield. Additionally, the ratio of σ2 GCA to σ2 SCA revealed nonadditive gene action in controlling the expression of phenol content, trichome density, number of damaged seeds and Fe and Zn content. Thus, breeder may focus efforts on desirable cross utilizing selection in further segregating generations for higher phenol content, trichome density and Fe and Zn content in addition to yield‐related traits while lesser number of damaged seeds per plant to concentrate for development of pod borer resilient high yielding kabuli genotypes to combat micronutrient deficiency. [ABSTRACT FROM AUTHOR]

In this study, distant hybridisation was successfully conducted between Brassica rapa var. rosularis Tsen et Lee ‘Huangxinwu’ (2n = 20, AA) and B. oleracea var. alboglabra Bailey ‘Big Yellow Flower Kale’ (2n = 18, CC). A total of three hybrids were obtained through artificial hybridisation and ovary culture. Forty asexual seedlings were obtained by propagation, and thirty were doubled. The identifications of morphological analysis, cytological observation, and SSR molecular analysis showed that one strain was a true hybrid. Allotetraploid hybrids exhibited generally an intermediate phenotype between their parents. The wrinkled leaf surface and leaf colour were more inclined toward the maternal parent, while its leaf thickness and size were more inclined toward the paternal parent. Furthermore, the allotetraploid hybrids showed obvious over-parent heterosis in biomass and nutritional quality characteristics, including plant weight, soluble sugar, VC, and cellulose, with corresponding contents of 882.76 g, 2.84%, 107.91 mg/100 g and 1.27%. Moreover, the soluble solids and soluble protein contents of these hybrids were 5.62% and 2.56 g/100 g, respectively, which were similar to those of the high-value parent. In general, the newly synthesised allotetraploid is an innovative germplasm of Brassica vegetables that can be used for future heterosis utilisation and nutritional quality improvement. [ABSTRACT FROM AUTHOR]

The preservation of genetic variation is fundamental in biodiversity conservation, yet its importance for population viability remains contentious. Mixed‐source reintroductions, where individuals are translocated into a single vacant habitat from multiple genetically divergent and often depauperate populations, provide an opportunity to evaluate how genetic variation and hybridization influence individual and relative population fitness. Population genetic theory predicts that individuals with higher genetic variation and hybrids among populations should have higher fitness. We tested these two hypotheses by analyzing individual and population‐scale data for westslope cutthroat trout (Oncorhynchus clarkii lewisi) in four mixed‐source reintroductions. We observed more hybrid and fewer nonhybrid offspring than expected across four independent mixed‐source reintroductions. We also found clear evidence that heterozygosity influenced individual reproductive and relative population fitness. Overall, we found a strong, positive relationship between genetic variation, hybridization, and transplant fitness, emphasizing the importance of genetic variation and population mixing in conservation. [ABSTRACT FROM AUTHOR]

An experiment was carried out to evaluate the level of heterosis and combining ability in cotton. Thirty five interspecific hybrids were generated by crossing five lines viz., GMS 14, GMS 17, GMS 19, GMS 21 and GMS 27 with seven testers namely CCB26, CCB51, DB1901, CCB2, CCB6, CO18 and Suvin in line x tester mating fashion. Twelve parents along with 35 hybrids and a standard check (DCH 32) were raised in a randomized block design with two replications to evaluate the combining ability and heterosis to identify good combiners and the best hybrids with high yield and fibre quality. The lines viz., GMS 14 and GMS 17 and the testers viz., CO 18 and Suvin were found to record significant gca effects for yield and fibre quality traits. Out of the 35 hybrids, GMS 14 x CO18, GMS 27 x Suvin and GMS 17 x CO18 recorded highly positive significant sca effects for most of the traits. The ratio between additive and dominant genetic variance was less than one for all the traits, indicating the preponderance of dominant gene action or non-additive gene action. The above three crosses also exhibited high heterosis over mid parent, better parent and standard check. Hence, these hybrids could be harnessed after analyzing their performance in yield trials. [ABSTRACT FROM AUTHOR]

The present research was conducted in Okra to study combining ability and gene action in a set of 28 F1s developed by crossing seven lines and four testers. The experiment was laid out in a Randomized Block Design with three replications and observations were recorded on 12 traits viz. days to 50% flowering, days to first picking, number of internodes, number of branches plant-1, fruit length at maturity and harvest, number of fruits plant-1, number of seeds fruit-1, seed index, fruit weight, yield per plant and plant height. The results revealed that two lines viz., VRO-4 and Sel2 were excellent general combiners for most of the traits in both positive and negative direction as per desirable traits. Cross VRO-6 x Varsha Uphar recorded highly significant SCA effects for eight traits and GAO-5 x GJO-3 for yield trait. Variance due to GCA was less than SCA, and the GCA/SCA ratio was less than unity indicating preponderance of nonadditive gene action for all the traits. This suggested the feasibility of exploitation of heterosis. [ABSTRACT FROM AUTHOR]

Twenty F1 s, parents and checks viz., MTU 1010 and RNR 15048 were assessed for grain yield and its contributing attributes to study combining ability and heterosis. The mean of hybrids was greater than that of the parents except for days to 50% flowering and plant height. For majority of the investigated characters, the analysis of variance indicated considerable variations among parents and hybrids. Degree of dominance was more than unity for majority of traits including grain yield. For the examined characters, SCA variances were equal to GCA variances, indicating the dominance of additive and non-additive gene activity. The traits days to 50 % flowering, plant height, panicle length, test weight, kernel length and kernel length/breadth ratio showed additive gene action whereas the remaining traits showed non-additive gene action. The gca effects revealed that among the lines IR 72 had significant gca effects in desired direction for yield and yield attributing traits. Among the 20 hybrids, MTU 1001 x Akshyadhan was found to be a good specific combiner for grain yield per plant. Similarly, the hybrids NLR 34449 x IR10N270 and IR 72 x IR10N270 were found to be good specific combiners for grain yield and yield contributing characters. The standard heterosis of these three hybrids was positively significant over the check varieties MTU 1010 and RNR 15048. Based on mean, sca and heterosis estimates, MTU 1001 x Akshyadhan, NLR 34449 x IR10N270 and IR 72 x IR10N270 were identified as promising hybrids. [ABSTRACT FROM AUTHOR]

The present investigation was undertaken in brinjal (Solanum melongena L.) to estimate combining ability and gene action following a half diallel mating design using ten parents. The ratio of genetic variance components, σ² gca/σ² sca and σ² D/σ² A, showed dominant gene action, indicating the presence of non-additive genetic variance for days to 50% flowering, fruit yield per plant, total phenol, antioxidant activity and total soluble sugar. The traits fruits per plant, fruit girth, and fruit weight showed additive genetic variance. Among the parental genotypes, AB 15-08, ABSR 2 and AB 20- 13 were found to be good general combiners for fruit yield, fruits per plant, and total soluble solids. The three highestranking hybrids were AB 15-08 × AB 20-13, AB 15-08 × AB 20-03 and AB 20-07 × GP BRJ 224. The above hybrids would be rewarding for harnessing heterosis. [ABSTRACT FROM AUTHOR]

The present investigation was undertaken to study the residual heterosis in F2 and F3 populations of Indian mustard [Brassica juncea (L.) Czern & Coss.]. The study material included eight parents and the 28 crosses of Indian mustard in two generations, namely F2 and F3. The experiment was conducted over two years at Uttar Banga Krishi Viswavidyalaya, Cooch Behar, West Bengal, during Rabi season 2020-21 and 2021-22. Out of the 28 crosses, three crosses namely, Npj-194 × DRMR-15-16, Npj-194 × RW- 85-59 (Sarma) and Npj-194 × SKJM-05 were found to show significantly positive residual standard heterosis over the standard variety (SKJM-05) for both the characters siliquae per plant and seed yield per plant. This provides us evidence that by improving siliquae per plant, the character seed yield per plant can be improved. The promising cross populations which have shown significant standard heterosis for seed yield in F2 and F3, can be utilized for the development of hybrid varieties, which would be very much beneficial to the marginal farmers of our country as they would be able to use the F2 and F3 seeds of the hybrid varieties without any compromise with seed yield. [ABSTRACT FROM AUTHOR]

Maize (Zea mays) represents one of the most successful uses of heterosis among crops. Hybrid maize seeds can be produced by crossing a male-sterile female parent with a male parent as the pollen donor to achieve high seed purity at low cost. Cytoplasmic male sterility (CMS) has been widely used for maize hybrid seed production. Recently, several hybrid seed production technologies based on genic male sterility (GMS) genes have been developed. In addition, the identification of environment-sensitive genic male sterility (EGMS) genes provides opportunities for the two-line system to be applied in maize hybrid seed production. In this review, we systematically summarize the male-sterile genes and molecular mechanisms of male sterility in maize. Future prospects for the study of maize male sterility are highlighted. Future research will enhance our understanding of the molecular regulatory networks of male sterility and promote the process of maize hybrid seed production using male sterile lines. [ABSTRACT FROM AUTHOR]

Exploring the biological potential of maize root architecture is one of the most important ways to improve nitrogen use efficiency (NUE). The NUE and its heterosis in maize hybrids have improved remarkably over decades. Yet, there is little research on maize hybrid heterosis for root architecture and its possible physiological relationship to heterosis for NUE. A field study lasting two years was carried out on four typical maize hybrids from old and new eras, including their parental inbred lines with two levels of nitrogen (0, 150 kg N ha−1). Compared to old-era maize hybrids, the brace root angle (BA) and crown root angle (CA) of new-era maize hybrids increased by 19.3% and 8.0% under 0 N, and by 18.8% and 7.9% under 150 N, which exhibited a steeper root architecture; the crown root number (CN) of new-era maize hybrids increased by 30.5% and 21.4% under 0 N and 150 N, respectively, which showed a denser root system; meanwhile, the depth of 95% cumulative root weight (D95) of new-era maize hybrids separately increased by 10.5% and 8.5% under 0 N and 150 N, which exhibited a deeper root distribution. This steeper-denser-deeper root architecture enhanced pre-anthesis N uptake and provided a premise of greater post-anthesis N remobilization. All maize hybrids displayed significant heterosis for root architecture compared to their parental inbred lines. The brace root branching (BB) and crown root branching (CB) of new-era maize hybrids and D95 have positive heterosis, while the BA, CA, and CB of old-era maize hybrids, brace root number (BN), and CN have negative heterosis. Regardless of whether root architecture heterosis was positive or negative, new-era maize hybrids showed an overall elevated trend compared to old-era maize hybrids. Structural equation modeling (SEM) showed that heterosis for nitrogen internal efficiency (NIE) was the primary reason for NUE heterosis in maize, influenced by heterosis for root architecture, which was steeper, denser, and deeper. Our results indicated that, compared with old-era maize hybrids, new-era maize hybrids had stronger heterosis for root architecture, which was beneficial to pre-silking nitrogen absorption and is an important physiological basis for the higher NIE heterosis and NUE heterosis in new-era maize hybrids. [ABSTRACT FROM AUTHOR]

In China, the main breeding objective for maize (Zea mays L.) is increasing the yield of single-cross hybrids. In this regard, developing yield-prediction models based on genetic markers for hybrids can enhance the probability of obtaining hybrid vigour in maize single-cross hybrids and reduce the cycle for germplasm development (inbred lines). In this study, we used simple sequence repeat markers to genotype 257 cross combinations from 97 commonly used maize inbred lines classified into four heterotic groups (Domestic Reid, P78599-type BSSS, Tangsipingtou, and Lvda Red Cob). We calculated the Q values (the probability of each individual's genomic variation coming from each subpopulation) of each inbred line's genetic components. We found that these reflected genetic distances between the parental inbred lines. The parental genetic difference was identified as a key factor influencing heterosis for yield performance of single-cross hybrids, and the interaction factors of Q values between the parents were found to be highly correlated with the accuracy of single-cross hybrid yield predictions. Moreover, we developed a yield-prediction model for maize single-cross hybrids based on our established equation: Y = 9480.2 − 2352.6R1R2 − 1411.8R1L2 + 94.1R1P2 + 1148.0R1S2 − 988.8L1R2 − 1016.9L1L2 − 655.7L1P2 − 1175.4L1S2 − 569.1P1R2 + 371.6P1L2 − 604.2P1P2 + 1684.7P1S2 + 733.1S1R2 + 726.9S1L2 + 924.2S1P2 − 1678.1S1S2 (the correlation coefficient r = 0.4778). Using this model for maize breeding, we achieved prediction accuracies of 66.7% and 76.9% for low and high-yielding single-cross combinations, thereby reducing the workload in field assessment experiments and improving breeding efficiency. [ABSTRACT FROM AUTHOR]

Acroceras macrum, a forage grass from Africa, offers potential for enhancing cattle production in subtropical flood-prone regions. Despite its use in Northeast Argentina since the 1980s, the lack of available fertile seeds limits its widespread adoption and large-scale cultivation. We evaluate a germplasm collection of hybrids generated for breeding purposes in Corrientes, Argentina. To assess the feasibility of breeding programs, we examined heterosis and heritability through phenotypic traits. We evaluated growth characteristics (initial vigor, ground cover), plant morphology (leaf and internode size), biomass production (across two sites and years), reproductive stem proportion, flowering peak timing, and seed filling (measured on four dates). Six families were assessed: four full-sibling families compared to the superior parent, and two half-sibling families. The timing of the flowering peak exhibited a correlation with photoperiod. All traits depended on parental combinations, exhibiting significant intra-familial variability ranging from negative heterotic hybrids exceeding 80% to positive hybrids reaching 90%. Correlations between heterosis of the traits and parents' genetic distance must be confirmed. Nevertheless, correlativeness was mainly observed for biomass production for distinct years and seasons. Hence, genetic distance could be a useful tool for the election of the parental combinations to improve this key trait in the species. Furthermore, heritability, was significant for most evaluated traits. It also could be exploited for breeding. This comprehensive assessment sheds light on the phenotypic behavior of A. macrum families, providing valuable insights for future breeding efforts aimed at enhancing its agronomic potential in subtropical regions prone to flooding. [ABSTRACT FROM AUTHOR]

Heterosis is a crucial factor in enhancing crop yield, particularly in sorghum (Sorghum bicolor). This research utilised six sorghum restorer lines, six sorghum sterile lines, and 36 hybrid combinations created through the NCII incomplete double-row hybridisation method. We evaluated the performance of F1 generation hybrids for leaf photosynthesis-related parameters, carbon metabolism-related enzymes, and their correlation with yield traits during the flowering stage. Results showed that hybrid sorghum exhibited significant high-parent heterosis in net photosynthetic rate (P n), transpiration rate (T r), stomatal conductance (G s), apparent leaf meat conductance (AMC), ribulose-1,5-bisphosphate (RuBP) carboxylase, phosphoenolpyruvate (PEP) carboxylase, and sucrose phosphate synthase (SPS). Conversely, inter-cellular carbon dioxide concentration (C i), instantaneous water uses efficiency (WUE), and sucrose synthase (SuSy) displayed mostly negative heterosis. Traits such as 1000-grain weight (TGW), grain weight per spike (GWPS), and dry matter content (DMC) exhibited significant high-parent heterosis, with TGW reaching the highest value of 82.54%. P n demonstrated positive correlations with T r, C i, G s, RuBP carboxylase, PEP carboxylase, GWPS, TGW, and DMC, suggesting that T r, C i, and G s could aid in identifying high-photosynthesis sorghum varieties. Concurrently, P n could help select carbon-efficient sorghum varieties due to its close relationship with yield. Overall, the F1 generation of sorghum hybrids displayed notable heterosis during anthesis. Combined with field performance, P n at athesis can serve as a valuable indicator for early prediction of the yield potential of the F1 generation of sorghum hybrids and for screening carbon-efficient sorghum varieties. There is limited information on the hybridisation of enzymes linked to these characteristics. Understanding hybrid dominance of photosynthetic traits and their associated enzymes in sorghum is crucial for identifying sorghum hybrids with highly dominant combinations and selecting suitable parents. This study utilised 36 sorghum hybrid F1 generations and their respective parents to assess hybrid dominance in leaf photosynthetic parameters, key enzyme activities during photosynthesis, yield formation, and other relevant factors, while also examining their correlation with yield in field conditions. This article belongs to the Collection Machine Learning for Plant Stress Phenotyping. [ABSTRACT FROM AUTHOR]

Heterosis of growth traits in economic fish has benefited the production of aquaculture for many years, yet its genetic and molecular basis has remained obscure. Nowadays, a new germplasm of hybrid Jinhu grouper (Epinephelus fuscoguttatus ♀ × E. tukula ♂), abbreviated as EFT, exhibiting paternal-biased growth heterosis, has provided an excellent model for investigating the potential regulatory mechanisms of heterosis. We integrated transcriptome and methylome to unravel the changes of gene expression, epigenetic modification, and subgenome dominance in EFT compared with maternal E. fuscoguttatus. Integration analyses showed that the heterotic hybrids showed lower genomic DNA methylation levels than the purebred parent, and the up-regulated genes were mostly DNA hypomethylation. Furthermore, allele-specific expression (ASE) detected paternal subgenome dominance-regulated paternal-biased heterosis, and paternal bias differentially expressed genes (DEGs) were wholly up-regulated in the muscle. Multi-omics results highlighted the role of lipid metabolism, particularly "Fatty acid synthesis", "EPA biosynthesis", and "Signaling lipids", in EFT heterosis formation. Coherently, our studies have proved that the eicosapentaenoic acid (EPA) of EFT was greater than that of maternal E. fuscoguttatus (8.46% vs. 7.46%). Finally, we constructed a potential regulatory network for control of the heterosis formation in EFT. Among them, fasn, pparg, dgat1, igf1, pomca, fgf8a, and fgfr4 were identified as key genes. Our results provide new and valuable clues for understanding paternal-biased growth heterosis in EFT, taking a significant step towards the molecular basis of heterosis. [ABSTRACT FROM AUTHOR]

SUMMARY: The utilization of rice heterosis is essential for ensuring global food security; however, its molecular mechanism remains unclear. In this study, comprehensive analyses of accessible chromatin regions (ACRs), DNA methylation, and gene expression in inter‐subspecific hybrid and its parents were performed to determine the potential role of chromatin accessibility in rice heterosis. The hybrid exhibited abundant ACRs, in which the gene ACRs and proximal ACRs were directly related to transcriptional activation rather than the distal ACRs. Regarding the dynamic accessibility contribution of the parents, paternal ZHF1015 transmitted a greater number of ACRs to the hybrid. Accessible genotype‐specific target genes were enriched with overrepresented transcription factors, indicating a unique regulatory network of genes in the hybrid. Compared with its parents, the differentially accessible chromatin regions with upregulated chromatin accessibility were much greater than those with downregulated chromatin accessibility, reflecting a stronger regulation in the hybrid. Furthermore, DNA methylation levels were negatively correlated with ACR intensity, and genes were strongly affected by CHH methylation in the hybrid. Chromatin accessibility positively regulated the overall expression level of each genotype. ACR‐related genes with maternal Z04A‐bias allele‐specific expression tended to be enriched during carotenoid biosynthesis, whereas paternal ZHF1015‐bias genes were more active in carbohydrate metabolism. Our findings provide a new perspective on the mechanism of heterosis based on chromatin accessibility in inter‐subspecific hybrid rice. Significance Statement: The utilization of rice heterosis is an essential avenue to overcome the yield bottleneck; however, the underlying molecular mechanism remains unclear. We characterized the more actively accessible chromatin state in the inter‐subspecific hybrid compared to that in its parents, revealing the regulation of chromatin accessibility and DNA methylation. This study offers a novel perspective on ACR as an embodiment of the regulation of hybrid rice. [ABSTRACT FROM AUTHOR]

Chili (Capsicum annuum L.) is an important functional food due to its main bioactive compound, capsaicin, and other nutritional phytochemicals. However, very few studies have been conducted to develop hybrids with a high content of nutritional phytochemicals. The present study involving six parents was conducted to identify superior hybrids with higher nutritional quality based on combining ability and heterosis following Griffing's diallel Method II Model I. A broad spectrum of genetic variation among the six parents and fifteen F1 hybrids was confirmed by analysis of variance. (H1/D)0.5 value indicated that partial dominance gene action controlled all the traits except capsaicin and total phenolic content. Based on general combining ability (GCA) results, parent P3 (PLP-2s) was the best general combiner for all the traits except K and Na, followed by the parents P6 (BU Capsicum 1), P5 (Morich-8), P4 (Chili Japan) and P1 (Red Chili). Specific combining ability (SCA), along with heterotic response, revealed that the F1 hybrid P3xP6 (PLP-2s x BU Capsicum 1) was the best hybrid, followed by the hybrids P4xP6 (Chili Japan x BU Capsicum 1) and P3xP4 (PLP-2s x Chili Japan), as they exhibited superiority for major nutritional components, such as capsaicin and ascorbic acid. Ultimately, the subsequent selection of the F1 hybrids would help develop better nutritional-quality hybrids. [ABSTRACT FROM AUTHOR]

A higher varietal specificity in the manifestation of traits in parental varieties was noted compared to hybrids. Two component traits of ear productivity in a series of generations were analyzed against the background of various factors, shifts in their average values and their impact on yield were predicted and determined. The phenotypic dominance index (hp) in the first generation was determined by the number of grains per ear and the weight of 1000 grains, combinations with a high level of heterosis were identified. Under the conditions of the Apsheron region, the effects of interaction between genotype and environment were determined in nine varieties of spring soft wheat and seven hybrid populations F1...F4 formed with their participation. A reliable effect of environmental conditions on all the studied traits was established. The contribution of the "year" factor to the number of grains per ear in varieties and hybrids was 10.9 and 13.9%, respectively; to the weight of 1000 grains - 5.8 and 19.5%; to the yield - 47.3 and 41.1%. The genetic component made a significant contribution to the weight of 1000 grains in varieties and hybrids (81.5 and 58.8%), as well as to the number of grains in varieties (38.4%). [ABSTRACT FROM AUTHOR]

Copyright of Journal of Plant Production is the property of Egyptian National Agricultural Library (ENAL) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Agricultural, Environmental & Veterinary Sciences is the property of Arab Journal of Sciences & Research Publishing (AJSRP) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Proper waste management will reduce several pollutions arising out of burning of different agri-wastes such as stubble burning of rice. The lignocellulose in the dry matter, can be converted into various essential products including biofuel through gasification and pyrolysis. This will help to reduce the cost by minimizing the import of petroleum products. A productive sustainable strategy is the development of energy-efficient rice varieties possessing desirable biomass traits without undermining the yield potential. For this sufficient genetic variability should be available to develop suitable dual-purpose varieties. Considering these points, initially, the molecular diversity in popular varieties for biomass traits was explored using cellulose synthase specific markers. An archeopteryx tree constructed thereof indicated the presence of sufficient diversity among the varieties. Eight potential varieties, having sufficient diversity among each other, were selected as parents for developing dual- purpose hybrids. Some of the superior crosses identified concerning both grain and straw yield per plant were Kanchan/Meher, Kanchan/Pratikshya, Pratikshya/Ankit, Hiranmayee/Chandrama and Kanchan/Meher. The crosses including Kanchan/Pratikshya, Meher/Pratikshya, Meher/Ankit, Pratikshya/Hiranmayee, Hiranmayee/Gobinda, Hiranmayee/Pradeep and Gobinda/Pradeep exhibited both positive significant relative heterosis and heterobeltiosis for the biochemical traits. Non-additive gene action was reported to involve in the inheritance of traits viz., plant height, biochemical traits and grain yield, whereas additive gene action played a crucial role in the inheritance of traits viz., leaf area, seed weight and straw yield. [ABSTRACT FROM AUTHOR]

Abstract Nicotine exhibits obvious heterosis, which can be used to create Nicotiana tabacum L. (tobacco) varieties with varying nicotine content. However, the reasons for the formation of nicotine heterosis and its relationship to nicotine transport and accumulation remain unknown. This study conducted a comprehensive analysis of six tobacco hybrids with varying heterosis levels and their parent materials from various aspects, such as phenotype, physiology, and transcriptomics. The results showed that the direct path coefficient of transport heterosis to nicotine heterosis was highest in hybrids, at 0.98, and a highly significant positive correlation between the two. The plant height, thick stalk circumference, large flow of tissue fluid in the stalk, and high nicotine concentration of tobacco were the underlying factors that led to the strong nicotine transport capacity of hybrids. The formation of nicotine transport heterosis in hybrids was mainly influenced by non-additive gene effects (accounting for 89.93%), with over-dominant effects playing a dominant role (accounting for 58.79%). Among non-additive expression DEGs, nicotine transporter related multi antimicrobial extrusion protein, drug/metabolite transporter, ABC family transporter, and glutathione S-transferase were significantly upregulated in hybrid strains. The RT-qPCR results indicated that these genes related nicotine transport also exhibited heterosis at the expression level. Our results revealed that the formation of nicotine heterosis is mainly achieved by enhancing the nicotine transport capacity in hybrids. The results are not only beneficial for promoting the theoretical study of nicotine heterosis in tobacco and the breeding and utilization of hybrids, but are also of great significance for guiding nicotine production and promoting its multipurpose utilization.

Abstract Okra (Abelmoschus esculentus L. Moench) is a vital vegetable crop known for its nutritional and economic significance, especially in tropical and subtropical regions. Studying heterosis and combining ability in okra is crucial for enhancing its yield, quality, and resistance to pests and diseases. Heterosis can lead to superior offspring with enhanced traits while understanding combining ability helps in identifying the best parent combinations for breeding programs. Okra is an often cross-pollinated crop; therefore, exploiting heterosis is advantageous. The study was conducted from 2021 to 2022 at the Experimental Farm and Quality Analysis Laboratory, Department of Vegetable Science, College of Horticulture, Dr Yashwant Singh Parmar University of Horticulture and Forestry, Nauni, Solan, Himachal Pradesh, India to evaluate the heterosis and combining ability in okra to facilitate the development of high-yielding, resilient cultivars. The experimental material consisted of an F1 population of 30 crosses obtained from 10 parental lines crossed with three testers in a Line × Tester mating design, plus a standard check (Punjab-8). Estimates of heterosis (heterobeltiosis and standard heterosis) of the cross combinations UHFO-6 × Pusa Bhindi-5, UHFO-6 × Arka Anamika and UHFO-9 × Arka Anamika were high for inter-nodal distance, number of pods per plant, average pod weight, pod yield per plant, harvest duration, hundred seed weight, mucilage content, etc. Higher estimates of general combining ability (GCA) effects for pod yield per plant were observed in the parental lines UHFO-6 (123.47) and UHFO-9 (7.49). Among the cross combinations, UHFO-10 × Hisar Unnat (38.81), UHFO-2 × Pusa Bhindi-5 (38.29), UHFO-2 × Arka Anamika (17.42), and UHFO-5 × Arka Anamika (15.06) demonstrated higher estimates of specific combining ability (SCA) effects for pod yield per plant. The cross UHFO-2 × Hisar Unnat (160.00) exhibited the highest heterobeltiosis for mucilage content, while UHFO-10 × Arka Anamika (562.03) showed the highest standard heterosis for total polyphenol content. These cross combinations could produce okra with enhanced nutritional and medicinal properties. The highest GCA and SCA effects for pod yield per plant were observed in UHFO-6 (123.47) and UHFO-10 × Hisar Unnat (38.81), respectively. Identifying these parental lines and cross combinations based on their combining ability can result in the development of okra hybrids with substantially higher yields. In future, after multi-location trials, these parents and crosses can be released to replace existing okra cultivars (hybrids/varieties). Higher yielding and better quality okra cultivars can enhance the profitability for farmers, contribute to food security, and meet market demands more efficiently.

Relevance. The research is devoted to studying the peculiarities of the high-parent heterosis manifestation which connected with yield traits and the biochemical composition of tomato fruits.Materials and Methods. The work was carried out in 2021–2023 in open field conditions on the experimental plot of the Belarusian State Agricultural Academy (Mogilev region, Belarus). The objects of research were 30 F1 hybrids and 11 parental forms with different levels of economically valuable traits and with the specific set of genes for pathogen resistance and lycopene accumulation. The aim of the research was to create high-yield heterotic F1 tomato hybrids, adapted to open field conditions in Belarus, with a valuable biochemical composition of fruits.Results. The best hybrid combinations showed an early yield of 0.90–2.49 kg/m2, a marketable yield of 7.50–11.40 kg/m2, and a total yield of 8.22–13.12 kg/m2. High heterosis effect was established for early (88.9–291.0%), marketable (36.0–111.2%), and total (28.6–97.8%) yield in some hybrids. Significant differences in the accumulation of dry matter, carotene, and soluble carbohydrates were ascertained between the hybrids. Hybrid combinations with the highest value of true heterosis on accumulation of dry matter (18.3–21.6%), carotene (20.2–22.9%), and soluble carbohydrates (15.7–38.9%) were identified. Inheritance of early, marketable and total yield, dry matter content, carotene and soluble carbohydrates predominantly took place according to the positive overdominance, fruit weight – according to the intermediate inheritance, vitamin C content – according to the negative overdominance. Hybrids Brusnichny F1, Mansiata F1, Rada F1 were transferred to the State Inspection for Testing and Protection of Plant Varieties of the Republic of Belarus and successfully passed the testing stage in 2023.

Abstract Heterosis, recognized for improving crop performance, especially in the first filial (F1) generation, remains an area of significant study in the tobacco industry. The low utilization of leaf veins in tobacco contributes to economic inefficiency and resource waste. Despite the positive impacts of heterosis on crop genetics, investigations into leaf-vein ratio heterosis in tobacco have been lacking. Understanding the mechanisms underlying negative heterosis in leaf vein ratio at the molecular level is crucial for advancing low vein ratio leaf breeding research. This study involved 12 hybrid combinations and their parental lines to explore heterosis associated with leaf vein ratios. The hybrids displayed diverse patterns of positive or negative leaf vein ratio heterosis across different developmental stages. Notably, the F1 hybrid (G70 × Qinggeng) consistently exhibited substantial negative heterosis, reaching a maximum of -19.79% 80 days after transplanting. A comparative transcriptome analysis revealed that a significant proportion of differentially expressed genes (DEGs), approximately 39.04% and 23.73%, exhibited dominant and over-dominant expression patterns, respectively. These findings highlight the critical role of non-additive gene expression, particularly the dominance pattern, in governing leaf vein ratio heterosis. The non-additive genes, largely associated with various GO terms such as response to abiotic stimuli, galactose metabolic process, plant-type cell wall organization, auxin-activated signaling pathway, hydrolase activity, and UDP-glycosyltransferase activity, were identified. Furthermore, KEGG enrichment analysis unveiled their involvement in phenylpropanoid biosynthesis, galactose metabolism, plant hormone signal transduction, glutathione metabolism, MAPK signaling pathway, starch, and sucrose metabolism. Among the non-additive genes, we identified some genes related to leaf development, leaf size, leaf senescence, and cell wall extensibility that showed significantly lower expression in F1 than in its parents. These results indicate that the non-additive expression of genes plays a key role in the heterosis of the leaf vein ratio in tobacco. This study marks the first exploration into the molecular mechanisms governing leaf vein ratio heterosis at the transcriptome level. These findings significantly contribute to understanding leaf vein ratios in tobacco breeding strategies.

Abstract High-quality red/dry chilli for spice, pharmaceutical and medicinal purposes is a major goal in chilli breeding. The male sterile lines have greater potential for the exploitation of heterosis in chilli to achieve this objective. Genetic male sterile lines with special traits like destalking and ability to withstand high rainfall were involved in heterosis breeding to identify hybrids for commercial and industrial purposes. Forty F1 hybrids were developed by crossing 4 diverse GMS lines with 10 testers using Line × Tester mating design to estimate heterosis, combing ability and gene action. The experiment involving 14 parents and 40 F1s, along with standard variety ‘CH-27’ was laid out in α-lattice square design in three replications during summer 2020 and 2021. The GMS lines MS 9-2 and MS 26-1 along with testers DPCh 10, VVG, DPCh 40 and Him Palam Mirch-2 showed significant GCA for marketable red/dry fruit yield and majority of their component traits. Ten F1 hybrids were identified with superiority for fruit yield based on mean performance, significant heterosis and SCA effects, providing an opportunity to utilize them in value-added products and dried spice purposes viz., MS 9-2 × HPM-2, MS 11-2 × DPCh 40, MS 9-2 × DPCh 40 and MS 9-2 × DPCh 101 with erect fruiting habit and that of MS 9-2 × DPCh 10, MS 26-1 × DPCh 10, MS 9-2 × PBC 535, MS 26-1 × VVG, MS 29-2 × DPCh 10 and MS 26-1 × DPCh 22- C with pendent fruits. The non-additive gene action was predominant in the expression of fruit yield, total red fruits/plant, oleoresin and capsanthin. A significant positive correlation among SCA, economic heterosis and per se performance is an indicative to identify superior hybrids. Multi-location testing of these hybrids shall pave way to exploit them commercially by making them available to the farmers.

Combining ability and heterosis were estimated in 45 rice hybrids generated by mating 10 parents, comprising both land races and advance breeding lines, in half diallel fashion. Hayman’s graphical analysis showed that all the twelve morphological traits studied had significant positive dominance variance. Narrow sense heritability was high for Days to fifty percentage flowering, Plant height, Panicle length and Test weight (> 30 %), and low for Grain yield per plant. According to the VrWr graph, traits like GYPP, PL, PH, TN and plot yield showed partial dominance, whereas traits like Blast disease index showed overdominance. A significant improvement over check was observed for heterosis and the crosses Mynri x CAUS103, Joha x CAUS107, CAUS 126 x CAUS107 and CAUS103 x CP, exhibited significantly positive standard heterosis for GYPP (>80 %) and PY (>100 %). Genetic distance based on fourteen markers revealed significant positive association with mid parent and better parent heterosis for Spikelet’s per plant, Filled grains per plant, Harvest index, Grain yield per plant, Panicle number and Plot yield. Therefore, it is evident that crosses with larger genetic distance between the parents gave hybrids with higher heterosis.

An experiment was carried out to evaluate the level of heterosis and combining ability in cotton. Thirty five interspecific hybrids were generated by crossing five lines viz., GMS 14, GMS 17, GMS 19, GMS 21 and GMS 27 with seven testers namely CCB26, CCB51, DB1901, CCB2, CCB6, CO18 and Suvin in line x tester mating fashion. Twelve parents along with 35 hybrids and a standard check (DCH 32) were raised in a randomized block design with two replications to evaluate the combining ability and heterosis to identify good combiners and the best hybrids with high yield and fibre quality. The lines viz., GMS 14 and GMS 17 and the testers viz., CO 18 and Suvin were found to record significant gca effects for yield and fibre quality traits. Out of the 35 hybrids, GMS 14 x CO18, GMS 27 x Suvin and GMS 17 x CO18 recorded highly positive significant sca effects for most of the traits. The ratio between additive and dominant genetic variance was less than one for all the traits, indicating the preponderance of dominant gene action or non-additive gene action. The above three crosses also exhibited high heterosis over mid parent, better parent and standard check. Hence, these hybrids could be harnessed after analyzing their performance in yield trials.

Combining ability and heterosis was investigated in mustard hybrids obtained from 7 × 7 half diallel cross. Twenty one F1s along with seven parents were evaluated in Randomized Complete Block Design. The combined analysis of variance revealed very significant differences among the parents for all morphological variables with the exception of secondary branches and siliqua length, indicating wide diversity among the parental material used in the present study. Significant GCA and SCA variance indicated additive and non-additive gene action across all the characters. The SCA variance components were larger than the GCA variance components for most traits indicating the prevalence of non-additive gene effects. Jawahar mustard × PM-30, showed a significantly positive SCA and better parent heterosis for seed yield per plant whereas five hybrids (Kranti × PM-30, Gujarat Mustard-3 × Pusa Mahak, Jawahar Mustard × PM-30, Jawahar Mustard × Pusa Mahak and PM-30 × Pusa Mahak) exhibited significant positive SCA effect for number of siliqua/ plant. Jawahar Mustard × PM-30, Varuna×Jawahar Mustard, Gujarat Mustard-3 × PM-30, exhibited highly significant heterosis over the mid-parent.

Abstract Background Hybrids are expected to show greater phenotypic variation than their parental species, yet how hybrid phenotype expression varies with genetic distances in closely-related parental species remains surprisingly understudied. Here, we investigate pelage and morphometric trait variation in anthropogenic hybrids between four species of Brazilian Callithrix marmosets, a relatively recent primate radiation. Marmoset species are distinguishable by pelage phenotype and morphological specializations for eating tree exudates. In this work, we (1) describe qualitative phenotypic pelage differences between parental species and hybrids; (2) test whether significant quantitative differences exist between parental and hybrid morphometric phenotypes; and (3) determine which hybrid morphometic traits show heterosis, dysgenesis, trangression, or intermediacy relative to the parental trait. We investigated cranial and post-cranial morphometric traits, as most hybrid morphological studies focus on the former instead of the latter. Finally, we estimate mitogenomic distances between marmoset species from previously published data. Results Marmoset hybrid facial and overall body pelage variation reflected novel combinations of coloration and patterns present in parental species. In morphometric traits, C. jacchus and C. penicillata were the most similar, while C. aurita was the most distinct, and C. geoffroyi trait measures fell between these species. Only three traits in C. jacchus x C. penicillata hybrids showed heterosis. We observed heterosis and dysgenesis in several traits of C. penicillata x C. geoffroyi hybrids. Transgressive segregation was observed in hybrids of C. aurita and the other species. These hybrids were also C. aurita-like for a number of traits, including body length. Genetic distance was closest between C. jacchus and C. penicillata and farthest between C. aurita and the other species. Conclusion We attributed significant morphometric differences between marmoset species to variable levels of morphological specialization for exudivory in these species. Our results suggest that intermediate or parental species-like hybrid traits relative to the parental trait values are more likely in crosses between species with relatively lesser genetic distance. More extreme phenotypic variation is more likely in parental species with greater genetic distance, with transgressive traits appearing in hybrids of the most genetically distant parental species. We further suggest that fewer developmental disturbances can be expected in hybrids of more recently diverged parental species, and that future studies of hybrid phenotypic variation should investigate selective pressures on Callithrix cranial and post-cranial morphological traits.